To prefix this, I don't think I'm a master at networks so maybe I'm misunderstanding something here. I noticed my NAT in video games was Moderate, which makes some actions quite difficult. The obvious fix for a moderate NAT is either UPnP or port forwarding.
We are in 2020, so manually setting up all 50+ ports that Steam requires (Destiny 2, Overwatch) is quite daunting. That is why UPnP just "works" and is so clever.
So now lets talk about the issue. I tell my router to disable DHCP and use my Pi-hole as the DHCP server, this helps so I can actually see which client is doing things. Instead of a generic router/IP owning all the outbound DNS requests.
This works great, but instantly causes my PC to result to a Moderate NAT when gaming. I imagine this is because with my DHCP server disabled on router, Pi-hole does not or can't communicate with UPnP on my main router (? - someone check me here)
I go back to DHCP on my router and immediately my game has an Open NAT. However, I don't see threads asking about this outside of this Reddit thread (https://www.reddit.com/r/pihole/comments/a8yivi/pihole_and_call_of_duty_black_ops_4_conection/)
So can anyone shed some light here? Is there a way to roll Pi-hole DHCP + UPnP? Or break it down where my logic is wrong? Am I doing something wrong?